1. Field of the Invention
The invention concerns diagnostic procedures performed on biological fluids and more particularly concerns a means and method of determining blood urea nitrogen concentrations in blood serum or plasma.
2. Brief Description of the Prior Art
Colorimetric techniques for the determination of blood urea nitrogen in blood were known prior to this invention; see for example Fearon, Biochem. Journ., 33, pages 902-7 (1939); Coulombe et al., Clinical Chemistry, 9, (1), pages 102-8, (1963); U.S. Pat. Nos. 3,511,611 and 3,732,007. Although the prior art techniques include the use of reagents based on diacetyl, such techniques have required performance by technical personnel having a fairly high degree of technical proficiency. One of the difficulties in blood urea nitrogen determinations employing diacetyl based reagents resides in the fact that diacetyl is relatively unstable. Therefore, the diacetyl based reagent must be freshly prepared immediately before use in carrying out a blood urea nitrogen analysis. Not only is a degree of technical proficiency required for the accurate preparation of a reliable reagent, but such preparation requires additional time and work on the part of the technician prior to his actually carrying out an analysis of an unknown specimen of blood serum or plasma.
The analysis kit of the present invention provides a means whereby a technician is provided with diacetyl reagent precursors in such form that the diacetyl reagent may be immediately prepared with a minimum of effort. The precursor reagents and consequently the kit per se is stable for a period of at least two years when stored out of direct sunlight and at room temperatures. Furthermore, the analysis kit according to the method of this invention provides for the uniform preparation of control reagents. The kit which forms part of this invention also reduces the complexity of the blood urea nitrogen analysis procedure so that it may be carried out by technicians having relatively little experience and training. The result of an analysis carried out employing the kit of the invention are uniform and compare remarkably well with more complex methods of determining blood urea nitrogen.
The method of the invention is particularly advantageous in that it permits for a highly accurate determination of blood urea nitrogen, with the expenditure of a minimum amount of time and effort on the part of technical personnel.